Difficulty recognizing speech in noise presents a great challenge to an older listener's ability to participate in social activities and obtain medicl care, often resulting in social isolation, cognitive decline, and psychological disturbance. Voice pitch, as defined by fundamental frequency (F0) in speech, is one of the most powerful cues for speech intelligibility in the presence of noise. While data from younger normal-hearing listeners suggest dynamic pitch cue is helpful for speech recognition in noise, some older listeners may be deprived of benefit from this cue because they cannot perceive it. Aim 1 of this proposal is to determine whether older listeners' individual ability to perceive dynamic pitch contributes to speech recognition in noise. We will use a pitch contour identification test to quantify dynamic pitch perception, while having a pitch discrimination test to control for ability to perceive stati pitch. The amount of difficulty understanding speech in noise will be measured by subjective and objective tests. Data will be acquired from both presbycusic and older near-normal hearing listeners to demonstrate a wide range of variability associated with hearing loss and aging. It is anticipated that the outcome of the Aim 1 experiments will serve as a foundation for devising customized clinical approaches that involve dynamic pitch perception as a potential contributor to speech-in-noise deficit. The efficacy of pitch contour for enhancing speech recognition also depends on the noise scenario and listener characteristics. Aim 2 of the proposal is to elucidate the environmental and listener factors modulating the efficacy of dynamic pitch cue for enhancing speech recognition in older adults with variability in age and hearing status. The benefit of dynamic pitch cue is defined by the differences in speech recognition performance across three target speech conditions (normal contour, flat contour, and strong contour). The amounts of benefit will be compared between modulated versus static noises, as well as between speech versus non-speech noises. It is predicted to be higher in modulated noise than in static noise, and to be higher in speech masker than in non-speech masker. Age and hearing loss are expected to influence the amount of benefit from dynamic pitch. The outcome of the Aim 2 experiments can direct development of technology and rehabilitation program that enhance the efficacy of dynamic pitch cue in these important noise situations.